Tile showers, floors and the layer under them. Warner Robins.

Beneath the tile

The part of a shower you never see decides whether it lasts.

On the rebuild in this photo the walls were boarded in Schluter KERDI-BOARD and sealed before a single tile went up. It is the step most people never see, so here is the wall, opened from the finished face back to the studs.

1. Surface

   Tile and grout

   What you see and what you clean: the field tile, the accent band, the niches, the tiled pan.

   If it is skipped: Tile and grout shed water. They do not stop it. A shower set straight onto drywall looks exactly the same on the day it is finished.

2. Bond

   Thinset bond coat

   Holds every tile to the board. Spread and combed so each tile beds down fully.

   If it is skipped: Hollow spots under a tile are where cracks start, usually a few months after the crew has gone.

3. Membrane

   Schluter KERDI-BOARD, seams sealed

   The layer that keeps water out of the wall. The boards go up, the joints and corners are sealed, and only then does tile go on.

   If it is skipped: Skip it and the first sign is a soft wall, a stained ceiling below or a smell, long after the grout still looks fine.

4. Structure

   Studs and framing

   Where a rebuild starts. The old wall comes out so the framing can be seen and squared before anything is fixed to it.

   If it is skipped: A wall out of plumb shows up later as lippage and tapered grout lines no amount of care at the tile stage can hide.